Shale inhibitor additives, wellbore fluids comprising said additives, and methods of using said fluids

Abstract

Shale inhibitor additives, wellbore fluids comprising said additives, and methods using said fluids control hydration in wellbores disposed within swellable subterranean formations. The wellbore fluids contain aqueous base fluids, the shale inhibition additives, and natural biopolymeric viscosifiers, and optional encapsulating polymer agents, wherein the shale inhibition additives include amine-based shale inhibition agents. The methods circulate the wellbore fluids into the wellbores and/or maintain triamine-based shale inhibition agents of the wellbore fluids at concentrations of at least 50% by weight, based on total weights of the shale inhibition additives during multiple circulations of the wellbore fluids in the wellbores.

What is claimed is: 
     
       1. A wellbore fluid, comprising:
 an aqueous base fluid; 
 a shale inhibition additive comprising at least one hydrophobic amine that is a neutralized byproduct of a Nylon-6,6 manufacturing process, wherein the at least one hydrophobic amine is present at a concentration of at least about 40% of a total active amine concentration of the shale inhibition additive; and 
 at least one polymeric viscosifier; 
 wherein the at least one hydrophobic amine comprises a triamine-based shale inhibition agent and a diamine-based shale inhibition agent, and a ratio of the triamine-based shale inhibition agent to the diamine-based shale inhibition agent is from about 3:1 to about 10:1, and 
 wherein the wellbore fluid facilitates at least one of an increase in bulk hardness, an increase in shale inhibition, an increase in inhibition agent adsorption, a decrease in clay dispersion, or a decrease in cation exchange activity when the wellbore fluid is introduced into a subterranean formation. 
 
     
     
       2. The wellbore fluid of  claim 1 , wherein the at least one polymeric viscosifier is selected from the group consisting of xanthan gum, diutan gum, gellan gum, welan gum, schleroglucan gum, and at least one mixture thereof. 
     
     
       3. The wellbore fluid of  claim 1 , wherein the diamine-based shale inhibition agent is present at a concentration of at least about 1% by weight and less than about 50% by weight, calculated to a total weight of the triamine-based shale inhibition agent and the diamine-based shale inhibition agent. 
     
     
       4. The wellbore fluid of  claim 1 , wherein the ratio of the triamine-based shale inhibition agent to the diamine-based shale inhibition agent is from about 5:1 to about 10:1. 
     
     
       5. The wellbore fluid of  claim 1 , wherein a concentration of the triamine-based shale inhibition agent is at least about 70% by weight, calculated to a total weight of the triamine-based shale inhibition agent and the diamine-based shale inhibition agent. 
     
     
       6. The wellbore fluid of  claim 1 , wherein the triamine-based shale inhibition agent comprises Bis(hexamethylene)triamine and the diamine-based shale inhibition agent comprises hexamethylenediamine. 
     
     
       7. The wellbore fluid of  claim 1 , wherein the wellbore fluid has a pH value of about 8.5 to about 11. 
     
     
       8. The wellbore fluid of  claim 1 , wherein the neutralized byproduct of a Nylon-6,6 manufacturing process comprises Bis(hexamethylene)triamine neutralized with at least one neutralizing acid, and wherein the shale inhibition additive has a pH value of at least about 9 and no more than about 11 and a water content of no more than about 40 percent by weight, calculated to a total weight of the shale inhibition additive. 
     
     
       9. The wellbore fluid of  claim 8 , wherein the at least one neutralizing acid is selected from the group consisting of hydrochloric acid, formic acid, and a combination thereof. 
     
     
       10. The wellbore fluid of  claim 8 , wherein the at least one neutralizing acid comprises concentrated hydrochloric acid and the water content of the shale inhibition additive is no more than about 30 percent by weight, calculated to a total weight of the shale inhibition additive. 
     
     
       11. The wellbore fluid of  claim 8 , wherein the at least one neutralizing acid comprises anhydrous HCl and the water content of the shale inhibition additive is about 0 percent by weight, calculated to the total weight of the shale inhibition additive. 
     
     
       12. The wellbore fluid of  claim 8 , wherein the at least one neutralizing acid comprises formic acid and the shale inhibition additive comprises a chloride-free inhibition additive. 
     
     
       13. The wellbore fluid of  claim 1 , wherein the at least one polymeric viscosifier comprises one or more natural biopolymers. 
     
     
       14. A method of drilling, the method comprising:
 circulating the wellbore fluid of  claim 1  in a wellbore disposed within a clay-containing subterranean formation, wherein the wellbore fluid has a pH value of about 8.5 to about 11. 
 
     
     
       15. The method of  claim 14 , wherein the neutralized byproduct of a Nylon-6,6 manufacturing process comprises Bis(hexamethylene)triamine neutralized with one or more neutralizing acids, and wherein the shale inhibition additive has a pH value of at least about 9 and no more than about 11 and a water content of no more than about 40 percent by weight, calculated to a total weight of the shale inhibition additive. 
     
     
       16. The method of  claim 14 , wherein the diamine-based shale inhibition agent comprises hexamethylenediamine. 
     
     
       17. The method of  claim 14 , wherein the triamine-based shale inhibition agent comprises Bis(hexamethylene)triamine. 
     
     
       18. A method of drilling, the method comprising:
 emplacing the wellbore fluid of  claim 1  in a wellbore during a first circulation of the wellbore fluid within the wellbore, wherein the wellbore is disposed within a clay-containing subterranean formation, the wellbore fluid has a pH value of about 8.5 to about 11; and 
 maintaining the concentration of the triamine-based shale inhibition agent at or above about 50% by weight, calculated to the total weight of the triamine-based shale inhibition agent and the diamine-based shale inhibition agent, during at least one subsequent second circulation of the wellbore fluid within the wellbore. 
 
     
     
       19. The method of  claim 18 , further comprising:
 loading the shale inhibition additive into the wellbore fluid before the first and the at least one subsequent second circulations such that the concentration of the triamine-based shale inhibition agent is at or above about 75% by weight, calculated to the total weight of the triamine-based shale inhibition agent and the diamine-based shale inhibition agent, during the first circulation and the at least one subsequent second circulation.